Field of the Invention
This invention relates to an irrigation system and method, and more specifically to drip irrigation systems with controllable flow gradients.
Description of Related Art
Irrigation systems for domestic crops, commercial landscapes, nurseries, and the like, often utilize irrigation management systems. A typical management system involves the programming of irrigation schedules, such that an entire area to be irrigated is irrigated en masse for a particular length of time, usually per day.
A time based irrigation management system has enabled irrigation of crops, plants, and landscapes to be performed automatically and on a regular schedule, but these systems have a deficiency in that they do not account for seasonal changes and local weather conditions. A basis of this drawback is that any system which is programmed to deliver any volume of water above and beyond the minimum amounted required may be considered to be wasteful of water resources. Conversely, the under delivery of water and nutrients can adversely affect production and profitability.
Water lost to evaporation may be minimized with the implementation of drip irrigation systems. In such a system, feeder lines may be used down rows of crops with water emitting devices spaced along the length of the feeder line. In passive systems, the water distributed along the length of the row is determined by the length of time that the feeder line is supplied with water pressure, but the relative distribution along the row remains constant. In some other systems, the water emitting devices along the length of the feeder line are actively controlled, such as with the use of an electrically controlled valve. With such a system, the water distribution may be precisely controlled.
A drawback with the passive system described above is that water distribution along the length of the row, relative to positions on that row, cannot be modified easily. A drawback with the precisely controlled system described above is that such a system is exorbitantly expensive, and also may need significant maintenance.
What is called for is an efficient and low cost system for altering water distribution along rows of crops during irrigation, such as irrigation of plant crops. What is also called for is such a system which lends itself well to being retrofitted into existing irrigation systems.